Dewaxing aid



Patented Dec. 23, 1541 DEWAXIN G AID Edwin C. Knowles, Beacon, N. Y., assignor, by

mesne assi gnments, to The Texas Company,

New York, N. Y., a corporation of Delaware No Drawing. Application August 23, 1938,

Serial No. 226,241

9 Claims.

This invention relates to the preparation and incorporation in wax-bearing mineral oil of an improved type of wax crystal regulating material and to the dewaxing of the oil in the presence of this regulating material. I

, The invention contemplates employing as a wax crystal regulator a product obtained by reacting fatty acids, fatty oils, metal soaps of fatty acids. and fatty acid esters having wax crystal regulating properties, with aluminum chloride at a temperature of around 175 to 350 F. The modified regulator so obtained is incorporated in the wax-bearing mineral oil and the oil dewaxed in the presence of the regulator and a dewaxing solvent. The mixture is chilled to precipitate wax and the wax so precipitated removed by liltration, centrifuging or cold-settling. The resulting dewaxed oil will have a relatively low saponification and neutralization number.

Advantageously, the wax crystal regulating material, after having been treated with aluminum chloride, is neutralized, as, for example, with ammonia, and the resulting mixture subjected to further heating at elevated temperature.

It is also contemplated employing the foregoing wax crystal regulator in conjunction with montan wax or the active ingredinets of montan wax. Montan wax, or its active ingredients, appear to exert a beneficial action upon the crystal structure of the higher melting point constituents of the wax, while the modified fatty acid or metallic soap of such fatty acid exerts its maximum effect upon those constituents of the wax which are of lower melting point and are precipitated over the lower range of chilling temperatures.

The fatty acids contemplated are carboxylic acids, such as stearlc, palmitic, oleic, linoleic, behenic and cerotic acid. Other acids are naphthenic acids and mixtures of naphthenic acids such as obtained in the refining of petroleum. Still other acids are abietic, ricinoleic, as well as oxidation products of paraflin wax.

The metallic soaps contemplated are the polyvalent metal soaps of the foregoing acids. Such metals, for example, are aluminum, lead, magnesium, zinc, chromium, etc.

The fatty oils may include lanolin, palm oil, tallow oil and olive oil, while fatty acid esters or fatty oils such as glycol and glycerol stearate are also contemplated.

Fatty acids and metallic soaps of fatty acids, such as mentioned above, have been employed heretofore in the prior art as wax crystal regulathe neutralization number of the dewaxed oil is due largely to hydrolysis in the presence of wet solvent or to the presence of free acids in ordinary metal soaps.

The object of the present invention, therefore,-

is to provide a dewaxing aid adapted for use in commercial plants without objectionably raising the neutralization number and the saponification number of the dewaxed oil. It has been found that modification of the fatty oil, fatty acid or fatty derivative, by treatment with aluminum chloride, under suitable conditions of temperature, preferably followed by neutralization with ammonia, produces a wax crystal regulator which does not cause this undesired increase in the saponification and neutralization value of the dewaxed oil.

The following example describes the procedure followed in modifying stearic acid and incorporating the resulting product in wax-bearing mineral oil for dewaxing:

About 20 grams of stearlc acid are dissolved in 30 grams of a light paraflin pale oil having 9. Saybolt Universal viscosity of around to 300 seconds at 100 F. Aluminum chloride is slowly added to the solution during agitation, while the solution is maintained at a temperature of around 300 to 350 F. The aluminum chloride is added to the solution in the proportion of from about one-quarter to one part by weight of aluminum chloride to one part of stearic acid. At higher temperatures, above 350 F., the resulting product tends to be less effective, while with temperatures below 300 F. the product is relatively cloudy in appearance after neutralization with ammonia, due to the presence of ammonium chloride. Hydrogen chloride gas is freely liberated during the first part of the reaction. When the addition of aluminum chloride is completed the reaction product is agitated and maintained at a temperature of 300 F. for about fifteen minutes.

Thereafter th reaction product is cooled to a temperature of about 140 to 150 F. and added to an additional quantity (about 350 grams) oi the pale oil to make a 5% solution.

Ammonia gas is then bubbled through the mixture at a temperature of 140 to 150 F. until the product smells strongly of ammonia. The reaction is then continued at 175 to 200 F. for a period of from one-half to one hour. The excess ammonia may be removed by reduction of the pressure to below atmospheric. The ammonia reaction temperature is advantageously maintained at around 200 F. or below. With higher temperatures of around 300 F. the product becomes less effective in the presence of wet dewaxing solvents.

The resulting product is of medium dark color and may be slightly cloudy. The cloudiness does not affect the utility of the product as a dewaxing aid and, if desired, can be removed by filtering the solution through a layer diatoms.- ceous earth without reducing the effectiveness of the product as a dewaxing aid.

This solution containing the modified regulator is then incorporated in the wax-bearing lubricating oil to be dewaxed at a temperature of around 120 or 130 F. Higher mixing temperatures are advantageous from the standpoint of conditioning the mixture so as to obtain the maximum benefit, as, for example, temperatures of around 150 F. and above.

The regulator is added to the wax-bearing oil to the extent such that the modified stearic acid consists of from about 0.05 to 1.0% by weight of the wax-bearing oil.

In the following example aluminum stearate was modified in a somewhat similar procedure. Thus, 10 grams of aluminum stearate were dissolved in 285 grams of the pale oil at a temperature oi. around 300 to 350 F. Anhydrous aluminum chloride was added slowly during agitation. The mixture was maintained at a temperature of around 300 to 350 F. Aluminum chloride was added in the proportion of one part of aluminum chloride to three parts of aluminum stearate by weight. Agitation of the mixture was continued for a quarter to one-half hour after the addition of the aluminum chloride had been completed or until the hydrogen chloride gas ceased to be freely liberated. Thereafter, the reaction product was cooled to a temperature of 140 to 150 F. and treated with ammonia gas. Following this, the mixture was subjected to a temperature of 1'75 to 200 F. for a period of from one-half to one hour.

If desired, the reaction of aluminum chloride can be carried out in a benzol solution. In such case a somewhat lower reaction temperature may be employed, as, for example, around 170 to 175 F.

A solution of the modified aluminum stearate in oil, containing around 5 to of modified stearate, is fluid at room temperature and in this respect is in marked contrast with solutions containing only 1 to 2% of untreated aluminum stearate which will set to a firm gel upon standing.

The use of only a small amount of the modified stearate is necessary as an efficient dewaxing aid, as, for example, 0.1% by weight of the chilled stock based upon the amount of aluminum stearate.

The following examples illustrate the improve ment obtained whenemploying the modified regulator as a dewaxing aid. In these examples,

the oil dewaxed was a solvent refined wax distillate derived from Mid-Continent crude, having a gravity A. P. I. or 29.6, Saybolt Universal viscosity at 210 F., 67.3 seconds, pour test 115 F., paraflin content 7.8%, and neutralization number 0.03 (milligram oi KOH per gram of oil).

The dewaxing solvent employed consisted of a mixture of 40% methyl ethyl ketone and 60% commercial benzol. Dewaxing was effected by chilling to a temperature or around 15 F. and filtering to produce an oil having a pour test 0! around 0 1''.

In each instance the regulator was used in conjunction with crude montan wax. Montan wax was incorporated in the dewaxing solventoil mix at a temperature of around 170 1''. and the mixture allowed to cool to 140 1". The additional stearic acid or aluminum stearate regulator in oil solution was then added.

Runs with stearic and modified stearic acid:

Gr ms I Neutraliza- Dcwaxing aid of :vax de v vs x d of cake oil 7m Percent Blank test 0.0% 146 66.0 0 (B Steeric acid (not modified 0.25 Ifiggtan was 0.05% X i. .7. ..?f.. 96 5 o0 ifled stesricsc 0. Montsn wax, 0.05% 0 33 5 12 Modified" stesric acid, 0.1 7

Montan was, 0.025% m a 03 Modification consisted of treating with aluminum chloride without subsequent treatment with ammonia.

" Modification consisted of treatment with aluminum chloride at F., followed by treatment with ammonia at 200 F.

Runs with aluminum stearate and modified aluminum stearate:

Modification consisted oi treating with aluminum chloride withouf s iibgggigiiit tnreatm ngit? tsmmonia. followed by tre tmgii t ith mm g n iz with aluminum chloride As the foregoing data indicate, when dewaxing the wax distillate in the conventional manner and in the absence of any added wax crystal regulator, a relatively large yield of wax cake was obtained, namely, around 146 grams. The yield of dewaxed oil was 65.0% of the charge and this oil had a neutralization number or 0.03.

When using the non-modified stearic acid and montan wax as a regulator the wax cake was reduced to 96 grams, but the neutralization number of the oil was increased to 0.60. Similarly, when using the non-modified aluminum stearate and montan wax, the wax cake was reduced to 53 grams, but the neutralization number of the oil was increased to 0.20.

On the other hand, when employing the modified stearic acid and montan wax, the wax cake was further reduced, while the neutralization number was also reduced to 0.12. This wasaccompanied by a very substantial increase in the yield of dewaxed 011. Even better results were obtained in the run using a stearic acid which had been modified by treatment with both aluminum chloride and ammonia. A comparable improvement was also realized in the case of the similarly modified aluminum stearate.

While the dewaxing of a wax distillate has been described in the foregoing examples, it is contemplated that the process is applicable to the dewaxing of other types of wax-bearing oils,-

including residual lubricating oil stocks.

Various solvents can be used for dewaxing, including the well-known and conventional dewaxing solvents and solvent mixtures. Satisfactory results are obtained by the use of a mixture of a wax anti-solvent and in an oil solvent such as a 1 hydroxide, potassium hydroxide, methyl amine,

calcium oxide, etc.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1'. The method of preparing a modified form of wax crystal regulator suitable as a dewaxing aid from a compound selected from the group consisting of fatty oils, fatty acids and the soaps and esters thereof having wax crystal regulating properties which comprises dissolving the compound in a low viscosity mineral lubricating oil, slowly adding aluminum chloride to the said solution during agitation thereof and while maintaining the solution at a temperature of around 300 to 350 F., continuing the agitation at elevated temperature for a few minutes after the addition of the chloride has been completed and until substantial liberation of hydrogen chloride gas ceases, and treating the reaction product with an alkaline neutralizing agent thereby producing a regulator which will not substantially increase the neutralization number of the dewaxed lubricating oil.

2. The method of preparing a modified form of wax crystal regulator suitable as a dewaxing aid froma compound selected from the group consisting of fatty oils, fatty acids and the soaps and esters thereof having wax crystal regulating properties which comprises dissolving the compound in a low viscosity mineral lubricating oil, slowly adding to said solution aluminum chloride in the proportion of around one-quarter to one part by weight of aluminum chloride to one part of the compound, agitating the solution during such addition and maintaining it at a temperature of around 300 to 350 F. for a period of around 15 to minutes after the addition is completed and until substantial liberation of hydrogen chloride gas ceases, treating the reaction product with an alkaline neutralizing agent while relatively hot, and thereafter subjecting the treated mixture to heating at a temperature of around 1'75 to 200 F. for a short period of time thereby producing a regulator which will not substantially increase the neutralization number of the dewaxed lubricating oil.

3. The method of preparing a modified form of wax crystal regulator suitable as a dewaxing aid from a compound selected from the group.

consisting of fatty oils, fatty acids and the soaps and esters thereof having wax crystal regulating properties which comprises dissolving the compound in a low viscosity mineral lubricating oil,

, slowly adding to said solution aluminum chloride in the proportion of around one-quarter to one part by weight of aluminum chloride to one part of the compound, agitating the solution during such addition and maintaining it at a temperature of around 300 to 350 F. for a period of around 15 to 30 minutes after the addition is completed and until substantial liberation of hydrogen chloride gas ceases, treating the reaction product with ammonia at a temperature of around to F., and subjecting the treated product to heating at a temperature of around to 200 F. for around 30 to 60 minutes thereby producing a regulator which will not substantially increase the neutralization number 'of the dewaxed lubricating oil.

4. The method according to claim 1 inwhich the fatty oil compound comprises, aluminum stearate.

5. The method according to claim 1 in which the fatty oil compound comprises stearic acid.

6. The method according to claim 3 in which the fatty oil compound comprises aluminum stearate.

7. The method according to claim 3 in which the fatty oil compound comprises stearic acid.

8. A wax crystal regulator suitable as a dewaxing aid obtained by reacting a compound selected from the group consisting of fatty oils, fatty acids and the soaps and esters thereof while dissolved in a low viscosity mineral lubricating oil with aluminum chloride in the proportion of around one-quarter to one part by around 175 to 300 F. for around 30 to 60 minutes.

9. A wax crystal regulator suitable as a dewaxing aid obtained by reacting a compound selected from the group consisting of fatty oils, fatty acids and the soaps and esters thereof while dissolved in a low viscosity mineral lubricating oil with aluminum chloride in the proportion of about one-quarter to one part by weight of aluminum chloride per part of said compound at a temperature of about 300 to 350 F., continuing the reaction for a few minutes until substantial liberation of the hydrogen chloride gas ceases, diluting the resulting reaction product with an additional quantity of said low viscosity oil to form a solution of about 5% concentration, treating the dissolved reaction product with ammonia at a temperature of about 140 to 150 F. and subjecting the said ammonia treated reaction product to heating at a temperature of about 175 to 300 F. for about 30 to 60 minutes.

EDWIN C. KNOWLES. 

